Method for producing a color filter, apparatus for manufacturing a color filter, electrooptic apparatus, and electronic device

ABSTRACT

An apparatus for manufacturing a color filter includes a stage on which a base having a target discharge area is adapted to be placed, a plurality of discharge heads having a first discharge head filled with a functional material, and a second discharge head filled with a liquid, and a control unit operatively coupled to the stage and the plurality of discharge heads. The control unit controls the stage and the plurality of discharge heads such that the stage and the plurality of discharge heads move relative to each other and a droplet of the functional material from the first discharge head and a droplet of the liquid from the second discharge head are discharged in the same target discharge area. The surface tension or viscosity is lower than that of the functional material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 11/040,004 filed on Jan. 24, 2005, now pending, which claimspriority to Japanese Patent Application No. 2004-038323 filed on Feb.16, 2004. The entire disclosures of U.S. patent application Ser. No.11/040,004 and Japanese Patent Application No. 2004-038323 are herebyincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for manufacturing a colorfilter, an apparatus for manufacturing a color filter, a color filterthus manufactured, an electrooptic apparatus having such color filter,and electronic device having such electrooptic apparatus.

2. Background Information

Display apparatuses have been widely used as devices for displayinginformation in recent years in notebook computers, mobile telephones,personal digital assistants, and other electronic devices. Liquidcrystal devices in which a color filter is disposed on a substrate toenable full color display have become commonplace. Methods formanufacturing such color filters can be classified by the material ofthe coloring portion and the manufacturing process, and the inkjetmethod has been proposed as a way to manufacture a color filter in whicha large number of color filters are formed on a substrate by dischargingcolored ink from nozzles. In the inkjet method, droplets are dischargedto a target film formation area, the discharged droplets wet the entiretarget film formation area, and the droplets are allowed to dry to forma target film. Examples of known film formation methods using inkjetting include methods of forming luminescent portions that aredisposed in a matrix form in a matrix display apparatus, and methods offorming the filter elements of a color filter substrate. JapaneseLaid-Open Patent Application No. 2003-127343 discloses such methods. Thepixel areas of the liquid crystal display described above are commonlyformed in a rectangular shape. In this case, a plurality of droplets isdischarged in the form of a matrix inside each pixel area.

However, it is ordinarily difficult to discharge droplets to theperiphery of the pixel area, and the droplets are discharged to aposition near the center of the pixel area. Since the distance from theedge of the droplet to the corner of the edge of the pixel area is far,it takes time for the discharged droplet to wet the pixel area byreaching all the way to the edge of the pixel area. There is also adrawback in that the droplets do not tend to spread to the edge of thepixel area due to the surface tension of the droplets discharged to thepixel area. The production efficiency of color filter substrates istherefore compromised. When drying begins before the discharged dropletswet the entire pixel area, it is difficult to form a color filteruniformly in the pixel area.

In view of the above, it will be apparent to those skilled in the artfrom this disclosure that there exists a need for an improved method formanufacturing a color filter, an apparatus for manufacturing a colorfilter, a color filter thus manufactured, an electrooptic apparatushaving such color filter, and an electronic device having suchelectrooptic apparatus thus that overcome the problems of the known art.This invention addresses this need in the art as well as other needs,which will become apparent to those skilled in the art from thisdisclosure.

SUMMARY OF THE INVENTION

The present invention was contrived to solve the above-describedproblems, and an object thereof is to provide a method of manufacturinga color filter whereby it is possible to form a color filter withuniform color saturation and to improve efficiency with which such colorfilters are manufactured.

Another object of the present invention is to provide electroopticapparatuses having such color filter and electronic device having suchelectrooptic apparatus, which have an excellent display quality.

The apparatus for manufacturing a color filter according to one aspectof the present invention includes a stage on which a base having atarget discharge area is adapted to be placed, a plurality of dischargeheads having a first discharge head filled with a functional material,and a second discharge head filled with a liquid, and a control unitoperatively coupled to the stage and the plurality of discharge heads,the control unit controlling the stage and the plurality of dischargeheads such that the stage and the plurality of discharge heads moverelative to each other and a droplet of the functional material from thefirst discharge head and a droplet of the liquid from the seconddischarge head are discharged in the same target discharge area. Thesurface tension or viscosity is lower than that of the functionalmaterial.

These and other objects, features, aspects and advantages of the presentinvention will become apparent to those skilled in the art from thefollowing detailed description, which, taken in conjunction with theannexed drawings, discloses a preferred embodiment of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is a schematic diagram of the color filter manufacturingapparatus in accordance with an embodiment of the present invention;

FIG. 2 is a view of the bottom surface of the carriage of the colorfilter manufacturing apparatus in accordance with the embodiment of thepresent invention, viewed from the stage side;

FIG. 3 is a view of the bottom surface of the head of the color filtermanufacturing apparatus in accordance with the present invention, viewedfrom the stage side;

FIG. 4( a) is a perspective view showing the configuration of thedischarge unit of the head of the color filter manufacturing apparatusin accordance with the present invention;

FIG. 4( b) is a cross sectional view of the discharge unit of the headof the color filter manufacturing apparatus in accordance with thepresent invention, viewed along the line 4B-4B shown in FIG. 4( a);

FIG. 5 is a block diagram showing the configuration of the control unitof the color filter manufacturing apparatus in accordance with thepresent invention;

FIG. 6( a) is a block diagram showing the configuration of the headdrive unit of the color filter manufacturing apparatus in accordancewith the present invention;

FIG. 6( b) is a timing chart of the signals to be transmitted from thehead drive unit of the color filter manufacturing apparatus inaccordance with the present invention;

FIG. 7( a) is a cross-sectional view of the color filter in accordancewith another aspect of the present invention;

FIG. 7( b) is a plan view of the color filter in accordance with thepresent invention;

FIG. 8 is a diagram showing the steps of manufacturing the color filterin accordance with another aspect of the present invention;

FIG. 9 is a diagram of showing the steps of manufacturing the colorfilter in accordance with another embodiment of the present invention,in which a liquid is discharged to the edge portion of the pixel area;

FIG. 10 is an exploded perspective view of the liquid crystal display asan embodiment of the electrooptic apparatus in accordance with stillanother aspect of the present invention;

FIG. 11 is a cross-sectional side view of the liquid crystal displayapparatus as the embodiment of the electrooptic apparatus of the presentinvention; and

FIG. 12 is a perspective view of the telephone as an embodiment ofelectronic device in accordance with still another aspect of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The method of manufacturing a color filter according to one aspect ofthe present invention includes providing a base having a targetdischarge area, discharging a functional material to the targetdischarge area on the base, and discharging a liquid to at least aportion of the target discharge area on the base. One of surface tensionand viscosity of the liquid is lower than the one of the surface tensionand the viscosity of the functional material.

In accordance with such a configuration, liquid is discharged to thetarget discharge area together with the functional material. Since thesurface tension or viscosity of the discharged liquid is low incomparison with the functional material, the functional material can wetthe entire area of the target discharge area quickly. As a result, sincethe liquid has already wetted the entire area on the substrate, thedischarged functional material wets the entire area, and a uniform filmcan be formed. Here, the liquid can be discharged to the targetdischarge area before or after the discharge of the functional materialto the target discharge area. For instance, when the functional materialis first discharged to the target area on the base and failed toadequately wet the area, the liquid having a lower surface tension orviscosity than that of the functional material is thereafter discharged,causing the functional material to wet the entire predetermined area andallowing a uniform film to be formed.

In the method of manufacturing a color filter according to anotheraspect of the present invention, the discharging of the liquid isperformed before the discharging of the droplet of functional material.

In accordance with such a configuration, liquid is first discharged to apredetermined area on the substrate. Since the surface tension orviscosity of the discharged liquid is low in comparison with thefunctional material, the liquid can wet the entire area of the targetdischarge area. Next, the functional material is discharged to the areaimmediately after the area has been covered with the liquid. As aresult, since the liquid has already wetted the entire area on thesubstrate, the discharged functional material wets the entire area, anda uniform film can be formed.

In the method of manufacturing a color filter according to anotheraspect of the present invention, the liquid is discharged toward an edgeportion of the target discharge area on the base.

In accordance with such a configuration, the liquid whose surfacetension or viscosity is lower than that of the functional material isdischarged solely to the edge portion of the target discharge area,which is ordinarily difficult to wet with a liquid material. Here, thefunctional material wets the entire predetermined area because thefunctional material is discharged onto the previously discharged liquidmaterial.

In the method of manufacturing a color filter according to anotheraspect of the present invention, the liquid is a solvent for thefunctional material.

In accordance with such configuration, since the liquid does not containa solute, and hence has lower viscosity in comparison with thefunctional material, making it possible to prevent insufficient wettingalong the edges of the target discharge area. The liquid is a solventfor the functional material, and therefore blends well without causingunintentional chemical reactions even when these materials are handledsimultaneously.

In the method of manufacturing a color filter according to anotheraspect of the present invention, the liquid includes a hot boiling pointsolvent for the functional material, and the functional materialincludes coloring ink.

In the method of manufacturing a color filter according to anotheraspect of the present invention, the liquid is discharged only towardthe edge portion of the target discharge area on the base. Since theliquid can be discharged solely to the edge portions of the area, theamount of liquid discharge can be reduced in comparison with the case inwhich the liquid is discharged to the entire target discharge area.Consumption of the liquid can therefore be reduced and economicefficiency improved.

In the method of manufacturing a color filter according to anotheraspect of the present invention, the surface tension of the liquid islower than that of the functional material.

The apparatus for manufacturing a color filter of the present inventionincludes a stage on which a base having a target discharge area isadapted to be placed, a plurality of discharge heads having a firstdischarge head filled with a functional material, and a second dischargehead filled with a liquid, and a control unit operatively coupled to thestage and the plurality of discharge heads, the control unit controllingthe stage and the plurality of discharge heads such that the stage andthe plurality of discharge heads move relative to each other and adroplet of the functional material from the first discharge head and adroplet of the liquid from the second discharge head are discharged inthe same target discharge area. The surface tension or viscosity islower than that of the functional material.

In accordance with such a configuration, the first discharge headsdischarge the functional material to the target discharge area on thebase. The second discharge heads discharge a liquid whose surfacetension or viscosity is lower than that of the functional material inthe target discharge area. The discharged liquid has a low surfacetension or viscosity in comparison with that of the functional material.Therefore, the functional material can wet the entire predetermined areaon the target discharge area. Here, the functional material can bedischarged before or after the discharge of the liquid from the seconddischarge head. When the liquid is discharged from the second dischargehead first, since the liquid has already wetted the entire area on thetarget discharge area, the functional material also wets the entiretarget discharge area, and a uniform film can be formed. Also, when thefirst discharge head first discharges the functional material to thetarget discharge area on the base, the target discharge area may notalways be adequately wetted with the functional material, but since thesecond discharge heads discharge the liquid whose surface tension orviscosity is lower than that of the functional material, the functionalmaterial wets the entire predetermined area, allowing a uniform film tobe formed.

The color filter in accordance with another aspect of the presentinvention is produced by the method of manufacturing a color filterdescribed above. The electrooptic apparatus in accordance with anotheraspect of the present invention is provided with such color filter.Examples of such electrooptic apparatus include liquid crystal displays,organic electroluminescent display apparatuses, plasma displayapparatuses, and other display apparatuses. Also, the electronic devicein accordance with still another aspect of the present invention isprovided with such electrooptic apparatus.

Selected embodiments of the present invention will now be explained withreference to the drawings. It will be apparent to those skilled in theart from this disclosure that the following descriptions of theembodiments of the present invention are provided for illustration onlyand not for the purpose of limiting the invention as defined by theappended claims and their equivalents.

First Embodiment

The apparatus for producing a color filter and the method formanufacturing a color filter according to the first embodiment of thepresent invention are described in detail with reference to thediagrams.

Apparatus for Manufacturing Color Filter

FIG. 1 is a schematic perspective view of the manufacturing apparatusfor a color filter 20 according to the present embodiment. Themanufacturing apparatus for a color filter 20 has a carriage 22, anX-axis direction guide shaft 2 for driving the carriage 22 along theX-axis direction, and an X-axis direction drive motor 3 for rotating theX-axis direction guide shaft 2, as shown in FIG. 1. Also, themanufacturing apparatus for a color filter 20 has a stage 4 for mountinga base 11, a Y-axis direction guide shaft 5 for driving the stage 4along the Y-axis direction, a Y-axis direction drive motor 6 forrotating the Y-axis direction guide shaft 5, and a base 7 to which theX-axis direction guide shaft 2 and the Y-axis direction guide shaft 5are each fixed in predetermined positions. A control unit 8 is providedto the lower portion of the base 7. The manufacturing apparatus for acolor filter 20 is furthermore provided with a cleaning mechanism 14 anda heater 15.

The X-axis direction drive motor 3 moves the carriage 22 along theX-axis direction and the Z-axis direction, which is orthogonal to theX-axis direction and the Y-axis direction, in accordance with signalsfrom the control unit 8. The X-axis direction drive motor 3 furthermorehas a function of turning the carriage 22 about an axis parallel to theZ-axis direction. The Y-axis direction drive motor 6 moves the stage 4along the Y-axis direction and the Z-axis direction in accordance withsignals from the control unit 8. The Y-axis direction drive motor 6furthermore has a function of turning the carriage 22 about the centerof an axis parallel to the Z-axis direction, as described above.

In the present embodiment, the X-axis direction may be described as thesub-scanning direction, and the Y-axis direction may be described as themain scanning direction. The imaginary origin of the X-, Y-, and Z-axesdirections is fixedly defined relative to the reference portion of themanufacturing apparatus for a color filter 20. The Z-axis direction isthe direction parallel to the vertical direction (direction ofgravitational acceleration).

The stage 4 has a plane parallel to both of the X- and Y-axesdirections. The stage 4 is configured so as to be capable of fixedlysupporting or holding thereon the base 11 that has a target dischargearea to which predetermined material is to be discharged. The stage 4 isfixedly held to the Y-axis direction guide shaft 5, and the Y-axisdirection drive motor 6 is connected to the Y-axis direction guide shaft5. The Y-axis direction drive motor 6 is a stepping motor or the like,and the Y-axis direction guide shaft 5 turns when a Y-axis directiondrive pulse signal is transmitted from the control unit 8. The stage 4moves along the Y-axis direction in association with the turning of theY-axis direction guide shaft 5.

The carriage 22 is fixedly held to the X-axis direction guide shaft 2,and the X-axis direction drive motor 3 is connected to the X-axisdirection guide shaft 2, as described above. The X-axis direction drivemotor 3 is a stepping motor or the like, and the X-axis direction guideshaft 2 turns when an X-axis direction drive pulse signal is transmittedfrom the control unit 8. The carriage 22 moves along the X-axisdirection in association with the rotation of the X-axis direction guideshaft 2. Thus, ink is discharged by causing the stage 4 to scan alongthe X-axis direction, and the carriage 22 along the Y-axis direction,with respect to the base 11 mounted on the stage 4. It should be notedthat the stage 4 and the carriage 22 can move relative to each otherwhile the stage 4 remains stationary and the carriage 22 alone is movedalong the X-axis direction, or while the carriage 22 remains stationaryand the stage 4 alone is moved along the Y-axis direction. In otherwords, “relative movement” or “relative scanning” includes moving onlyone of the stage 4 and the carriage 22 with respect to the other. Thedetails regarding the carriage 22 are described later.

The control unit 8 calculates the relative position, discharge amount,and other parameters regarding the coloring ink 16 (an example offunctional material) and dispersion medium 17 (liquid with a lowersurface tension or viscosity than that of the function material) to bedischarged, and discharge data is output to the inkjet head groups 26and stage 4 on the basis of this calculated discharge data. The detailsregarding the control unit 8 are described later.

Configuration of Heads

FIG. 2 is a schematic diagram showing the configuration of the heads 24viewed from the base 11. A plurality of heads 24 having substantiallythe same configuration is mounted on the carriage 22, as shown in FIG.2. Two rows each having 12 heads 24 are mounted on the carriage 22 alongthe Y-axis direction. The 12 heads 24 in each row are divided into foursets of head groups 26 (head groups 26A, 26R, 26G, and 26B). In otherwords, the four sets of head groups 26 include: the head group 26A(first discharge heads) in which the heads 24 are filled solely withdispersion medium 17 used to disperse or dissolve the coloring ink 16,the head group 26R in which the heads 24 are filled with red coloringink 16R (second discharge heads), the head group 26G in which the heads24 are filled with green coloring ink 16G (second discharge heads), andthe head group 26B in which the heads 24 are filled with blue coloringink 16B (second discharge heads). In the present embodiment, the headgroup 26A in which dispersion medium 17 alone is filled dischargesdispersion medium 17 to an entire pixel area on the substrate before anyof the above-described head groups 26R, 26G, and 26B discharges coloredinks 16R, 16G, and 16B to the pixel area.

Each head groups 26 is provided with three heads 24, as described above.The positions of these three heads 24 are arranged so as to be offset inthe lengthwise direction of the heads 24. The three heads 24 that are ineach of the head groups 26 are referred to as head 24 a, head 24 b, andhead 24 c in the order from the top to bottom along the Y axisdirection. The head 24 a of the head group 26A, the head 24 a of thehead group 26R, the head 24 a of the head group 26G, and the head 24 aof the head group 26B are disposed in the same position on the X axisdirection. In a similar fashion, the heads 24 b and 24 c of the headgroups 26A, 26R, 26G, and 26B are also disposed on the same positions onthe X axis direction.

In accordance with such a configuration, the colored inks 16R, G and Bcan be discharged from the head groups 26 to the pixel area immediatelyafter the dispersion medium 17 has been discharged from the head group26A. As a result, the colored inks 16R, G, and B can be dischargedbefore the dispersion medium 17 previously discharged to the pixel areaevaporates.

Additionally, in accordance with such a configuration, since thedischarge medium 17 initially discharged onto the substrate does notcontain coloring ink 16, the viscosity is low in comparison with adispersion medium that contains the coloring ink 16. The dispersionmedium 17 initially discharged onto the substrate therefore wets theentire pixel area on the base 11. Right after that, one of the coloredinks 16R, G, and B is discharged immediately thereafter to the pixelarea completely wetted by the dispersion medium 17. The coloring ink 16therefore wets the entire pixel area. As a result, nonuniformity causedby insufficient wetting of the edges of the pixel area on the substratecan be prevented, and a uniform film can be formed.

Here, butyl carbitol acetate (BCTAC) or the like is preferably used asthe dispersion medium 17 filled in the head group 26A. Other examples ofa high-boiling solvents suitable as the dispersion medium other than theabove-described dispersion medium 17 include solvents based ondiethylene glycol dialkyl ethers expressed by the formulaR¹—O(CH₂CH₂O)₂—R² (wherein R¹ and R² each independently represent analkyl group with a carbon number of 4 to 10); solvents based ontriethylene glycol dialkyl ethers expressed by the formulaR³—O(CH₂CH₂O)₃—R⁴ (wherein R³ and R⁴ each independently represent analkyl group with a carbon number of 1 to 10); solvents based onpolyethylene glycol dialkyl ethers expressed by the formulaR⁵—O(CH₂CH₂O)_(i)—R⁶ (wherein R⁵ and R⁶ each independently represent analkyl group with a carbon number of 1 to 10, and i is an integer from 4to 30); solvents based on propylene glycol dialkyl ethers expressed bythe formula R⁷—OCH(CH₃)CH₂O—R⁸ (wherein R⁷ and R⁸ mutually independentlyrepresent an alkyl group with a carbon number of 4 to 10); ester basedsolvents such as those based on glycerol triacetate (triacetin),di-n-butyl maleate, di-n-butyl fumarate, n-butyl benzoate, dimethylphthalate, diethyl phthalate, di-n-propyl phthalate, di-i-propylphthalate, di-n-butyl phthalate, di-amyl salicylate, and the like. Itshould be noted that the organic solvent of the coloring ink 16 is asolvent with a boiling point of 250° C. or higher at one atmosphericpressure (hereinafter referred to as “high-boiling point solvent”).

In the present invention, an organic solvent with a boiling point oflower than 250° C. (hereinafter referred to as “low-boiling pointsolvent”) may be jointly used with the high-boiling point solvent.Examples of such low-boiling point solvent include ethylene glycolmonoalkyl ethers such as ethylene glycol monomethyl ether, ethyleneglycol monoethyl ether; ethylene glycol monoalkyl ether acetates such asethylene glycol monomethyl ether acetate; diethylene glycol monoalkylethers such as diethylene glycol monomethyl ether; diethylene glycolmonoalkyl ether acetates such as diethylene glycol monomethyl etheracetate; propylene glycol monoalkyl ether acetates such as propyleneglycol monomethyl ether acetate; ethers such as diethylene glycoldimethyl ether; alcohols such as 1-octanol; ketones such as methyl ethylketone; carboxylic acids such as caproic acid; alkyl esters of lacticacid such as 2-hydroxypropionic acid methyl; and other esters such as2-hydroxy-2-methyl propionic acid ethyl; aromatic hydrocarbons such astoluene and xylene. The amount of a low-boiling point solvent to beused, is ordinarily 20 wt % or less, and preferably 5 wt % or less, withrespect to the total weight of the high-boiling point solvent and thelow-boiling point solvent.

A predetermined amount of dispersion medium 17 is blended with thecoloring ink 16R, coloring ink 16G, and coloring ink 16B filled in theheads 24, such that the coloring ink is dispersed or dissolved in thisblended dispersion medium 17. This is due to the fact that the viscosityof the discharged ink must be set to a low value in order to allow thedroplets of ink to be discharged from the inkjet nozzles withoutblocking the nozzles. The coloring ink 16 has pigments, binder resins,and high-boiling point solvents (organic solvents) as requiredcomponents, and in certain cases may also contain multifunctionalmonomers, photoinitiators, or other additives.

The color tone of the pigment is not particularly limited to anyspecific colors, and may be suitably selected in accordance with how theresulting color filter is designed to be used. A pigment, dye, ornatural coloring matter may be used, but an organic pigment or inorganicpigment is used in particular.

Examples of suitable organic pigments include compounds classified as“Pigments” in the Color Index (C.I.; published by The Society of Dyersand Colourists), and more specifically include Pigment Yellows such asC.I. Pigment Yellow 1, 3, 12; Pigment Oranges such as C.I. PigmentOrange 1, 5, 13; Pigment Reds such as C.I. Pigment Red 1, 2, 3; andPigment Blues such as C.I. Pigment Blue 15, 15:3, 15:4. These organicpigments may be used singly, or as a mixture of two or more of them.

Examples of the inorganic pigment include titanium oxide, bariumsulfate, calcium carbonate, zinc flower, lead sulfate, yellow lead, redoxide (red iron oxide (III)), cadmium red, ultramarine, Prussian blue,chrome oxide green, cobalt green, amber, titanium black, synthetic blackiron oxide, carbon black, and other inorganic pigments.

The binder resin is preferably a polymer containing a carboxylic group,particularly a copolymer (hereinafter referred to as a “carboxylgroup-containing copolymer (B1)”) composed of an ethylenic unsaturatedmonomer having at least one carboxyl group (hereinafter referred to as a“carboxyl group-containing unsaturated monomer”) and anotherpolymerizable ethylenic unsaturated monomer (hereinafter referred to as“other unsaturated monomer (b1)”). Examples of the carboxylgroup-containing unsaturated monomer include acrylic acid, methacrylicacid, and crotonic acid.

Examples of the other unsaturated monomer (b1) include styrene, vinyltoluene, methoxystyrene, vinyl benzyl methyl ether, and other aromaticvinyl compounds, as well as methyl acrylate, methyl methacrylate, andother unsaturated carboxylic acid esters.

The carboxyl group-containing copolymer (B1) is preferably a copolymercomposed of acrylic acid and/or methacrylic acid and at least one typeof compound out of styrene, methyl acrylate, methyl methacrylate,2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, benzyl acrylate,benzyl methacrylate, polystyrene macromonomer, and polymethylmethacrylate macromonomer

The surface tension of the dispersion medium 17 is preferably in a rangeof 0.02 N/m or higher and 0.07 N/m or lower. If the surface tension isless than 0.02 N/m when the liquid is discharged by the inkjet method, aflight curve tends to occur because the wetting characteristics of theink composition on the nozzle surface increase. When the surface tensionexceeds 0.07 N/m, control of the discharge amount and timing becomesdifficult because the shape of the meniscus does not stabilize at thetip of the nozzle.

In order to adjust the surface tension, a nonionic-based,fluorine-based, or silicone-based surface tension adjuster can be addedin a small amount to the dispersion medium 17 in a range doing so doesnot unreasonably reduce the contact angle with the base 11. The nonionicsurface tension adjuster is useful for improving the wettingcharacteristics of the liquid relative to the base, thereby improvingthe leveling characteristics of the film, preventing occurrence of bumpsand peeling in the film, and providing other advantages.

The dispersion medium 17 may contain organic compounds such as alcohols,ethers, esters, ketones as required.

The viscosity of the dispersion medium 17 is preferably 1 mPa·s orhigher and 50 mPa·s or lower. The is because if the viscosity is lessthan 1 mPa·s when the ink is discharged with the inkjet method, the areaaround the nozzle is easily soiled by the ink flow, and if the viscosityis higher than 50 mPa·s, the nozzles tend to get clogged more thefrequently, and it is difficult to achieve smooth droplet discharge.

The dispersion medium 17 filled the head group 26A and the dispersionmedium 17 loaded into the head group 26R, G and B may be of the sametype or of different types.

FIG. 3 shows the bottom surface of one of the heads 24. The shape of thebottom surface of the heads 24 is configured as a polygon having twolong sides and two short sides. The lengthwise direction of the bottomsurface of the heads 24 corresponds to the X-axis direction, and thewidth direction corresponds to the Y-axis direction. Also, the bottomsurface of the heads 24 faces the stage 4.

A plurality of nozzles 28 is formed as ink discharge ports on the bottomsurface of the head 24. It should be noted that in the presentembodiment 180 nozzles 28 are disposed with a predetermined spacing HXPtherebetween. The nozzles 28 aligned in two nozzle rows 1A and 1B arealigned in a staggered fashion along the X-axis direction. Also, 90nozzles 28 are aligned with a predetermined spacing LPN in each of thenozzle rows 1A and 1B. However, several nozzles 28 on each end of thenozzle rows 1A and 1B are designated as “inactive nozzles” from whichink is not discharged, and the other nozzles 28 are designated as“discharge nozzles” from which ink is to be discharged. Piezoelectricelements 38 are separately provided to each of the nozzles 28, asdescribed below. As a result, the nozzles 28 can independently carry outthe discharge operation. In other words, the discharge amount of thedroplets, the discharge time, and other discharge parameters can becontrolled for each nozzle 28 in accordance with the electrical signalfed to the piezoelectric elements 38.

FIG. 4( a) is a perspective view showing the configuration of thedischarge unit of a head 24. The discharge unit of the head 24 isprovided with a nozzle plate 42 and a vibration plate 40, and thesecomponents are connected via a plurality of partitions 36. A pluralityof cavities 34 and a liquid reservoir 44 are formed by the plurality ofpartitions 36. The plurality of cavities 34 and the liquid reservoir 44are connected via supply ports 33. The liquid reservoir 44 is connectedto a hole 46, and the coloring ink 16 or the dispersion medium 17 is fedthrough the hole 46 to be filled in the liquid reservoir 44 and cavities34. Nozzles 28 for discharging the coloring ink 16 or the dispersionmedium 17 from the cavities 34 are formed in the nozzle plate 42.

FIG. 4( b) is a cross-sectional view along the line B-B of the head 24shown in FIG. 4( a). A piezoelectric element 38 is configured so that apiezoelement 38C is held between a pair of electrodes 38A and 38B. Thecontrol unit 8 applies a predetermined voltage to the pair of electrodes38A and 38B. The piezoelectric element 38 to which voltage has beenapplied mechanically vibrates so that the piezoelectric element 38 andthe vibration plate 40 vibrate in unison due to the piezoelectriceffect. The pressure inside the cavity 34 is varied thereby, and thecoloring ink 16 or the dispersion medium 17 is fed from the supply port33 to the liquid reservoir 44 and the cavity 34. When the voltageapplied to the piezoelectric element 38 is stopped in such a state, thepiezoelectric element 38 and vibration plate 40 return to their originalstates, the pressure in the cavity 34 therefore changes again, and theink in the cavities 34 is discharged from the nozzle hole 32 of thenozzle 28 to the base. It should be noted that an electrothermalconverter may be used instead of a piezoelement.

Control Unit

FIG. 5 is a block diagram showing the configuration of the control unit8. The control unit 8 is operatively connected to the X-axis directiondrive motor 3, the Y-axis direction drive motor 6, and the heads 24, soas to be selectively controllable. The control unit 8 has an inputbuffer memory 200. The input buffer memory 200 receives ink dischargedata from an external information processing apparatus. The dischargedata is composed of data indicating the relative position of all thetarget discharge areas on the base, data indicating the number ofrelative scans required to apply the ink up to a predetermined thicknessin all the target discharge areas, data specifying nozzles that willfunction as ON (discharge) nozzles, and data specifying nozzles thatwill function as OFF (inactive) nozzles. The input buffer memory 200feeds the discharge data to the processor 204, and the processor 204stores the discharge data in the storage device 202. It should be notedthat the storage device 202 in FIG. 5 is RAM.

The processor 204 sends the scan drive unit 206 data indicating therelative positions of the nozzles with respect to the target dischargearea on the base based on the discharge data in the storage device 202.The scan drive unit 206 sends the X-axis direction drive motor 3 and theY-axis direction drive direction motor 6 shown in FIG. 5 drive signalscorrelated with the discharge data and the discharge cycle EP shown inFIG. 6. As a result, the head 24 scans the target discharge area in arelative fashion. The processor 204, on the other hand, sends the headdrive unit 208 selection signals SC for specifying the ON/OFF state ofthe nozzles at each discharge timing based on the discharge cycle EP andthe discharge data stored in the storage device 202. The head drive unit208 sends the head 24 ejection signals ES, which are required for inkdischarge, based on the selection signals SC. As a result, ink isdischarged as droplets from the designated nozzles 28 of the head 24.

FIG. 6( a) is a block diagram showing the configuration of the drivehead unit. FIG. 6( b) is a timing chart of the signals in the head driveunit. The head drive unit 208 has a single drive signal generator 203and a plurality of analog switches AS, as shown in FIG. 6( a). Theanalog switches AS are provided for each of the piezoelectric elements38 in the head 24. The drive signal generator 203 is designed togenerate and feed a drive signal DS to the analog switches AS. The drivesignal DS contains a plurality of discharge waveforms W that arerepeated in the discharge cycle EP, as shown in FIG. 6( b). Thedischarge waveform W corresponds to the drive voltage waveform that isto be applied between the pairs of electrodes 38A and 38B of thecorresponding piezoelectric element 38 in order to discharge a singledroplet from the nozzle 28.

The volume of the droplets to be discharged from the head 24 iscontrolled by the discharge waveform W. In view of the above, the dataof the discharge waveform W that allows droplets of a predeterminedvolume to be discharged is input to the drive signal generator 203, andthe drive signal generator 203 generates a drive signal DS based on thedischarge waveform W data. However, the drive signal generator 203 maybe configured to receive the data indicating the required volume of thedroplets, calculate a discharge waveform W from the data, andautomatically generate a drive signal DS. In this case, a table forcorrelating the volume of the droplets and the discharge waveform W isinput to the drive signal generator 203 in advance. With such aconfiguration, the amount of data input to the drive signal generator203 can be reduced.

A plurality of selection signals SC (SC1, SC2, . . . ) for controllingthe ON/OFF state of the nozzles 28 is fed to the analog switches ASshown in FIG. 6( a). The selection signals SC can assume either a highlevel state or a low level state, as shown in FIG. 6( b). The analogswitches AS shown in FIG. 6( a) feed ejection signals ES (ES1, ES2, . .. ) to one of the electrodes 38A and 38B in the piezoelectric element 38in accordance with the drive signal DS and the selection signals SC.When the selection signal SC is at a high level, a drive signal DS istransmitted as an ejection signal ES, as shown in FIG. 6( b).Conversely, when the selection signal SC is at a low level, a referencepotential L is transmitted as the ejection signal ES. Since thereference potential L is provided to the other of the electrodes 38A and38B in the piezoelectric element 38, the coloring ink 16 or thedispersion medium 17 is discharged from the nozzle 28 corresponding tothe piezoelectric element 38 when a drive signal DS is applied to oneelectrode in the piezoelectric element 38, as shown in FIG. 6( a).

Structure of Color Filter

FIG. 7( a) is a cross-sectional view showing the structure of a colorfilter substrate. The color filter substrate 50A is provided with anoptically transparent carrier base 54, a black matrix 50 formed on thecarrier base 54, and a bank 58 formed on the black matrix 50. Pixelareas are formed in areas partitioned by the black matrix 50. The pixelareas partitioned and defined by the black matrix 50 are composed oftarget discharge areas 18R, 18G, and 18B in a predetermined pattern. Thetarget discharge area 18R is an area in which a filter layer is to beformed for emission of light exclusively in the red wavelength range,the target discharge area 18G is an area in which a filter layer is tobe formed for emission of light exclusively in the green wavelengthrange, and the target discharge area 18B is an area in which a filterlayer is to be formed for emission of light exclusively in the bluewavelength range.

FIG. 7( b) is a plan view of the structure of the color filter. Thesubstrate 50A is positioned in an imaginary plane that is parallel toboth of the X- and Y-axes directions. The pixel area has a polygonalshape composed of long and short sides. The lengthwise direction of thepixel area corresponds to the X-axis direction, and the width directioncorresponds to the Y-axis direction. The X- and Y-axes directions areorthogonal to each other. A plurality of target discharge areas 18R,18G, and 18B formed on the carrier base 54 are periodically arranged inthe form of a matrix. Specifically, the target discharge areas 18R, 18G,and 18B are each disposed in a single row along the X-axis direction,and are furthermore each periodically disposed in the cited order with apredetermined spacing along the Y-axis direction. The spacing betweenthe target discharge areas 18R along the Y-axis direction in this caseis the predetermined spacing LRY. The target discharge areas 18G andtarget discharge areas 18B are similarly disposed with predeterminedspacing LGY and spacing LBY along the Y-axis direction.

Method of Manufacturing Color Filter Substrate

Next, an example of the method of forming the color filter, black matrix50, and bank 58 of the present embodiment is described below.

First, the black matrix 50 made of a black resin is formed on thecarrier base 54. Specifically, a negative resist with a black pigmentcontaining carbon particles or other particles, an acrylic or other typeof resin monomer, and a polymerization initiator as main components areapplied by spin coating or another method to the front surface of thecarrier base 54, and the resist is thereafter prebaked. Next, the resistis exposed in a predetermined position using a photomask on which thepattern of the black matrix 50 is formed. The polymerization reaction ofthe monomer progresses and the exposed resist becomes a resin that isinsoluble in a solvent. Lastly, the exposed unnecessary portions aloneare allowed to remain by developing the resist, and a black matrix 50with a predetermined pattern can be formed.

The black matrix 50 with a predetermined pattern composed of chromium oranother metal, or a metal compound can be formed in the followingmanner, for example. First, a black matrix 50 with a predeterminedpattern can be formed by depositing chromium or another metal, or ametal compound in the form of a film across the entire surface of thecarrier base 54 by sputtering or another method, and thereafter forminga predetermined pattern by photolithography.

Next, a bank 58 is formed on the black matrix 50 obtained by theabove-described method. The bank 58 is formed by applying aphotosensitive resist for the bank 58 to the entire surface of thecarrier base 54 by spin coating or another method, exposing anddeveloping the resist with the same method as when the black matrix 50composed of black resin was formed, and forming a bank 58 with apredetermined pattern.

Next, a color filter is formed using the manufacturing apparatus for acolor filter. In the present embodiment, the inkjet method is adopted asthe manufacturing apparatus for a color filter.

FIG. 8( a) is a diagram showing the step of discharging the dispersionmedium 17 to a target discharge area 18 on the base 54. First, thecontrol unit 8 causes the bottom surface of the heads 24 of the carriage22 mounted on the manufacturing apparatus for a color filter to face thecarrier base 54, as shown in the diagram. The dispersion medium 17 isdischarged from the nozzles 28 of the head 24A to the pixel areas on thecarrier base 54 as the carriage 22 is moved relative to the carrier base54. At this time, the X-axis direction of the target discharge areas 18and the nozzles 28 of the heads 24 are aligned so as to be substantiallyparallel, and the dispersion medium 17 is sequentially discharged fromthe nozzles 28 of the heads 24A when the nozzles 28 arrive at the areasabove the target discharge areas 18.

Specifically, the carriage 22 begins to scan in the width direction ofthe pixel area, that is, along the Y-axis direction. This scanningcauses the rows 1A, 1B, 2A, 2B, 3A, and 3B of nozzles 28 of the headgroups 26A to enter into the target discharge areas 18R to which thedispersion medium 17 is to be discharged. The rows 1A, 1B, 2A, 2B, 3A,and 3B of the nozzles 28 discharge the dispersion medium 17 in sequenceas they arrive in the areas above the target discharge areas 18R. Thehead groups 26A subsequently enters into the target discharge areas 18Gthat are adjacent along the Y-axis direction (main scanning direction)to the target discharge areas 18R to which the dispersion medium 17 hasbeen discharged, and the dispersion medium 17 is discharged onto thetarget discharge areas 18G. Next, the head groups 26A sequentially enterinto the target discharge areas 18B that are adjacent to the targetdischarge area 18G along the Y-axis direction, and the dispersion medium17 is discharged onto the target discharge area 18G. In this manner, thehead groups 26A discharge the dispersion medium 17 to all the targetdischarge areas 18, instead of discharging the dispersion medium 17exclusively to specific target discharge areas 18 of the head groups26R, G, or B.

This action is carried out with respect to all the target dischargeareas 18R, G, and B, which are disposed in the scanning direction of theY-axis direction, and the dispersion medium 17 is thus discharged. Whenthe scan along the Y-axis direction is completed, the control unit 8causes the head groups 26A to move in a relative fashion along theX-axis direction. When the head groups 26A move to the target dischargeareas 18R that are adjacent along the X-axis direction, scanning isstarted once again along the Y-axis direction, and the dispersion medium17 is discharged by repeating the above-described method with respect toall the target discharge areas 18R, G, and B to which the dispersionmedium 17 has not yet been discharged.

Banks 58 that function as partitions 36 are formed along the peripheryof the pixel areas that form the target discharge areas 18R, G, and B.The dispersion medium 17 should be preferably discharged so that centerportions of the coloring inks 16R, G, and B discharged to the targetdischarge areas 18R, G, and B are higher than the highest bank 58, andyet the coloring inks 16 do not flow into neighboring pixel areas.

FIG. 8( b) is a diagram showing the step for discharging the coloringinks 16 to be performed after the step of discharging the dispersionmedium 17. The head groups 26A subsequently pass over the targetdischarge areas 18R, and the head groups 26R enter the target dischargeareas 18R as shown in the diagram. Since the target discharge areas 18Rcorrespond to the head groups 26R, the control unit 8 sends a drivesignal DS to the piezoelectric elements 38 so as to cause the coloringink 16R to be discharged to the target discharge areas 18R.

The head groups 26R are configured so that the rows 1A, 1B, 2A, 2B, 3A,and 3B of nozzles 28 of the head groups 26R sequentially enter thetarget discharge areas 18R to which the dispersion medium 17 has beendischarged, as described above. When the rows 1A, 1B, 2A, 2B, 3A, and 3Bof nozzles 28 sequentially arrive above the target discharge areas 18R,the coloring ink 16R is sequentially discharged. The head groups 26Rsubsequently enter the target discharge areas 18G that are adjacentalong the Y-axis direction to the target discharge areas 18R to whichthe coloring ink 16R has been discharged. In this case, since the headgroups 26R do not need to discharge the coloring ink 16R to the targetdischarge area 18G, no discharge occurs. The head groups 26R enter intothe target discharge areas 18B that are adjacent to the target dischargeareas 18G along the Y-axis direction, and next target discharge areasthat are adjacent in the Y-axis direction. The coloring ink 16R isdischarged when the head groups 26R above the next target dischargeareas 18R.

This action is carried out with respect to all the target dischargeareas 18R disposed in the scanning direction of the Y-axis direction,and the coloring ink 16R is discharged. When the scan along the Y-axisdirection is completed, the control unit 8 causes the head group 26R tomove in a relative fashion along the X-axis direction. When the headgroup 26R moves to the target discharge area 18R that is adjacent alongthe X-axis direction, scanning is started once again along the Y-axisdirection, and the coloring ink 16R is discharged by repeating theabove-described method for all the target discharge areas 18R to whichthe coloring ink 16R has not yet been discharged.

In a similar fashion, the head groups 26G and 26B discharge coloringinks 16G and 16B to their corresponding target discharge areas 18.

As a drying step, the carrier base 54 is subsequently placed in a dryingoven for 10 minutes at 100° C. to vaporize the dispersion medium 17. Thedrying temperature should be in a range of 30° C. to 200° C., and thedrying time should be two minutes or more.

FIG. 8( c) is a diagram showing the drying step after the coloring ink16 has been discharged. A color filter having the coloring portions R,G, B in a predetermined pattern is formed by heating the coloringportions formed in the target discharge areas 18R, G, and B at atemperature of about 150° C. to 270° C., and baking (curing) thecoloring portions R, G, B, as shown in this diagram.

In accordance with the present embodiment, the dispersion medium 17 isfirst discharged to a pixel area on the base. The dispersion medium 17is less viscous than the coloring ink 16 dispersed or dissolved in thedispersion medium 17. For this reason, the dispersion medium 17 has alow contact angle with the base and therefore is able to wet the entirepixel areas quickly on the base.

The coloring inks 16 that have been dispersed or dissolved in thedispersion medium 17 are discharged to the pixel areas on the baseimmediately after the dispersion medium 17 has been discharged. As aresult, since the dispersion medium 17 has already wetted the entirepixel areas on the base, the coloring ink 16 that is subsequentlydispersed or dissolved in the dispersion medium 17 can wet the entirepixel areas quickly, and a uniform film can be formed.

Alternative Manufacturing Method

Described above is the case in which the dispersion medium 17 loadedinto the head group 26A is discharged to the entire pixel areas.Described below is the case in which the dispersion medium 17 isdischarged to the edges of the pixel areas. It should be noted thatother than the fact that the dispersion medium 17 is discharged to theedges of the pixel area, the steps described herein is the same as themethod for manufacturing a color filter described above. Therefore,description of steps of the method of manufacturing a color filter ofthe alternative embodiment that are similar to those of theabove-described method if manufacturing a color filter of the firstembodiment is omitted.

FIG. 9 is a schematic view of the case in which the liquid material isdischarged to the edges of the pixel area. The head groups 26A scanalong the Y-axis direction the target discharge areas 18R to which thedispersion medium 17 is to be discharged. The rows 1A, 1B, 2A, 2B, 3A,and 3B of nozzles 28 of the head group 26A enter into the targetdischarge areas 18R in this order. At this time, the control unit 8selects rows of nozzles 28 of the head groups 26A that are at positionsthat overlap with the positions of the edges of the target dischargeareas 18R, and the dispersion medium 17 is discharged toward the edgesof the target discharge areas 18R.

First, when row 1A of the nozzles 28 in the heads 24 a of the head group26A enters the target discharge area 18R, for example, the control unit8 selects the nozzles 28 that will come to positions above the edges ofthe target discharge areas 18R from among the nozzles 28 disposed in row1A. In the present embodiment, the nozzle 281 of row 1A will reachposition exactly above the edge of the target discharge area 18R.Therefore, the control unit 8 transmits a drive signal DS fordischarging the dispersion medium 17L1 from nozzle 281 to thepiezoelectric element 38 corresponding to nozzle 281. As a result, thedispersion medium 17L1 is discharged from the nozzle 281 of row 1Atoward the edge of the target discharge areas 18R.

Next, row 1B of the nozzles 28 of head 24 a enters the target dischargeareas 18R. In this case, the control unit 8 selects nozzle 282 of row 1Bof the nozzles 28 because nozzle 282 of row 1B will reach a positionabove the edge of the target discharge area 18R. The control unit 8transmits a drive signal DS for discharging the dispersion medium 17L2from the nozzle 282 of the row 1B to the piezoelectric element 38corresponding to nozzle 282. As a result, the dispersion medium 17L3 isdischarged from the nozzle 282 of row 1B toward the edge of the targetdischarge area 18R. Similarly, the nozzle 281 of the row 2A correspondsto the position of the edge of the target discharge area 18R. Thus, thedispersion medium 17L3 is discharged from the nozzle 281 of the row 2A.

In the similar manner, the nozzles 28 corresponding to the positions ofthe edges of the target discharge areas 18 are selected from the nozzles28 of the other heads 24 in a similar fashion according to the methoddescribed above, and the dispersion medium 17 is discharged to the edgesof the target discharge areas 18.

The control unit 8 transmits a drive signal DS for preventing thedischarge of the dispersion medium 17 to nozzles 28 that do notcorrespond to positions of the edges of the target discharge area 18R.When row 1A of the nozzles 28 enters the target discharge area 18R, forexample, the nozzle 282 of row 1A of the nozzles 28 is not associatedwith the edge of the target discharge area 18R, and a drive signal DSthat prevents the discharge of the dispersion medium 17 is thereforetransmitted to the piezoelectric element 38 corresponding to nozzle 282.As a result, the dispersion medium 17 is not discharged from the nozzle282 corresponding to this piezoelectric element 38. The row 1A of thenozzles 28 enters the target discharge area 18G which is adjacent to thetarget discharge area 18R in the scanning direction, and theabove-described discharge operation is repeated.

In a similar fashion in accordance with the method described above, whennozzles 28 of the other heads 24 are not positioned in positions thatare associated with the edges of the target discharge areas 18, suchnozzles 28 enter into the neighboring target discharge areas 18 withoutdischarging the dispersion medium 17

In accordance with such a configuration, the dispersion medium 17 can bedischarged only to the edges of the pixel area, which are ordinarilydifficult to wet with liquid material alone. For this reason, thecoloring ink 16 discharged onto the pixel area to which the dispersionmedium 17 has already been discharged wets the entire pixel area,including the edges of the pixel area. As a result, a color film withuniform color saturation can be formed. Also, since the dispersionmedium 17 is required to be discharged solely to the edges of the pixelarea, the consumption of liquid material can be suppressed in comparisonwith the case in which the liquid material is discharged to the entirepixel area, resulting in an economically efficient method ofmanufacturing the color filter.

Electrooptic Apparatus

The electrooptic apparatus is composed of the color filter formed asdescribed above. The general configuration of a liquid crystal displayapparatus, which is an example of an electrooptic apparatus, will now bedescribed with reference to FIGS. 10 and 11. In the presentspecification, the liquid crystal layer side is referred to as the“inner side” of the various elements of the liquid crystal displayapparatus.

FIG. 10 is an exploded perspective view of the liquid crystal displayapparatus 1, and FIG. 11 is a cross-sectional side view taken along theline 11-11 of FIG. 10. The liquid crystal display apparatus 1 isconfigured so as to hold a liquid crystal layer 88 between a first base70 and a second upper base 80, as shown in FIG. 10. A nematic liquidcrystal or another liquid crystal is used for the liquid crystal layer88, and twisted nematic (TN) mode is adopted as the operating mode ofthe liquid crystal display apparatus 1. A liquid crystal other than thatdescribed above may be used, and an operating mode other than thatdescribed above may also be adopted. Described below is an example of anactive matrix liquid crystal display apparatus that uses TFD elements asswitching elements, but the present invention may be applied to anactive matrix liquid crystal display apparatus other than the apparatusdescribed below, or to a passive matrix liquid crystal displayapparatus.

In the liquid crystal display apparatus 1, the first and secondsubstrates 70 and 80, which are composed of glass or another transparentmaterial, are disposed in opposing positions, as shown in FIG. 10.

A plurality of data lines 81 is formed on the inner side of the secondbase 80. A plurality of pixel electrodes 82 composed of ITO or anothertransparent electroconductive material is disposed in the form of amatrix on the side of the data lines 81. The pixel area is composed ofareas for forming the pixel electrodes 82. The pixel electrodes 82 areconnected to the data lines 81 via TFD elements 83. The TFD elements 83are composed of a first electroconductive film primarily composed of Taand formed on the surface of the second base 80, an insulating filmprimarily composed of Ta₂O₃ and formed on the surface of the firstelectroconductive film, and a second electroconductive film primarilycomposed of Cr and formed on the surface of the insulating film(so-called MIM structure). The first electroconductive film is connectedto the data lines 81, and the second electroconductive film is connectedto the pixel electrodes 82. The TFD elements 83 thereby function asswitching elements that control passage of the current through the pixelelectrodes 82.

A color filter film 72 is formed as described above on the inside of thefirst base 70. The color filter film 72 is composed of color filters72R, 72G, and 72B in a substantially rectangular shape from a plan view.The color filters 72R, 72G, and 72B are composed of pigment or othercoloring material that exclusively transmits their respectivelydifferent colors of light, and are disposed in the form of a matrix incorrespondence with the pixel areas. Also, a light-blocking film 77 isformed on the periphery of the color filters in order to prevent lightfrom intruding from neighboring pixel areas. This light-blocking film 77is formed in the shape of a frame and is composed of black chromiummetal or another material having light-absorbing properties. Atransparent insulating film 79 is furthermore formed so as to cover thecolor filter film 22 and the light-blocking film 77.

A plurality of scanning lines is formed on the inside of the insulatingfilm 79. The scanning lines are composed of ITO or another transparentelectroconductive material, are formed in a substantially striped shape,and are extended in the direction orthogonal to the data lines 81 of thesecond base 80. The scanning lines are formed so as to cover the colorfilters 72R, 72G, and 72B, which are aligned in the direction in whichthe scanning lines extend, and are designed to function as counterelectrodes.

When scanning signals are transmitted to the scanning lines and a datasignal is transmitted to the data lines 81, an electric field is appliedto the liquid crystal layer 88 by the opposing pixel electrodes 82 andthe counter electrodes 86.

Orientation films 74 and 84 are formed so as to cover the pixelelectrodes 82 and the counter electrodes 86, as shown in FIG. 11. Theorientation films 74 and 84 control the orientation of the liquidcrystal molecules when an electric field is applied to the liquidcrystal layer 88. The orientation films 74 and 84 are composed ofpolyimide or another organic polymer material, and are provided withrubbed surfaces. The liquid crystal molecules in the lengthwisedirection near the surface of the orientation films 74 and 84 align inthe rubbing direction when an electric field is applied, and aredesigned to become aligned in a direction substantially parallel to theorientation films 74 and 84. It should be noted that the orientationfilms 74 and 84 are rubbed so that the orientation direction of theliquid crystal molecules near the surfaces of the orientation film 74and the orientation direction of the liquid crystal molecules near thesurface of the orientation film 84 are offset relative to each other bya predetermined angle. The liquid crystal molecules in the liquidcrystal layer 2 are thereby designed to be helically laminated along thethickness direction of the liquid crystal layer 88.

The substrates 70 and 80 are joined at the periphery by a sealingmaterial 89 composed of a heat-curing, UV-curing, or another type ofcuring adhesive. The liquid crystal layer 88 is sealed inside the spaceenclosed by the bases 70 and 80 and the sealing material 89. It shouldbe noted that the thickness (cell gap) of the liquid crystal layer 88 iscontrolled by spacer particles 90 disposed between the two bases 70 and80.

Polarizing plates (not shown) are disposed outside the first and secondsubstrates 70 and 80. The polarizing plates are disposed so that themutual polarization angles (transmission axes) are offset by apredetermined angle. Also, a backlight (not shown) is disposed outsidethe polarizing plate on the light incident side, which is below thefirst base 70 in FIG. 11.

The light emitted from the backlight is converted to linearly polarizedlight along the axis of polarization of the polarizing plate on thelight incident side, and is allowed to enter the liquid crystal layer 88from the first substrate 70. This linearly polarized light turns by apredetermined angle along the twisted direction of the liquid crystalmolecules when passing through the liquid crystal layer 88 to which anelectric field has not been applied, and leaves the polarizing plate onthe light emitting side. White is thereby displayed (normally whitemode) when an electric field is not applied. Conversely, when anelectric field is applied to the liquid crystal layer 88, the liquidcrystal molecules are oriented to become perpendicular to theorientation films 74 and 84 along the direction of the electric field.In this case, the linearly polarized light that has entered the liquidcrystal layer 88 does not change direction and therefore does not leavethe polarizing plate on the light emitting side. Black is therebydisplayed when an electric field is applied. It should be noted that agrayscale can be displayed by manipulating the strength of the appliedelectric field.

The liquid crystal display apparatus 1 is configured as described above.

Electronic Device

FIG. 12 is a perspective view showing an example of electronic devicerelated to the present invention. The mobile telephone 1300 shown in thediagram is provided with the above-described electrooptic apparatus as asmall-sized display unit 1301, and is also provided with a plurality ofoperating buttons 1302, an earpiece 1303, and a mouthpiece 1304.

The electronic devices in which the above-described electroopticapparatus can be used is not limited to the above-described mobilephone, and advantageous application may also be made as an image displaydevice in electronic books, personal computers, digital still cameras,liquid crystal television, video tape recorders with viewfinders ordirect-view monitors, car navigation systems, pagers, personal digitalassistants, calculators, word processors, work stations, TV phones, POSterminals, and all types of equipment provided with a touch panel.Electronic device with excellent display quality can be achieved in anyof these applications.

These inventions can provide electrooptic equipment and electronicdevice that have excellent display quality.

The technological scope of the present invention is not limited to theembodiments described above and also includes various modification tothe embodiments described above within a range that does not depart fromthe spirit of the invention. In other words, the specific materials,configurations, and other aspects listed in the embodiments are no morethan examples, and suitable modifications are possible. Described in theabove embodiments, for example, is a method for discharging droplets toa target discharge area by disposing the heads so that the nozzle rowsare substantially parallel to the lengthwise direction of a targetdischarge area, and moving the heads along the width direction of thetarget discharge area. In contrast, it is also possible to use themethod for discharging droplets to a target discharge area and to carryout the film formation method according to the present invention byplacing the heads so that the nozzle rows are substantially parallel tothe width direction of a rectangular target discharge area, and movingthe heads along the lengthwise direction of the target discharge area.Also described in the above embodiments is a method for discharging aliquid whose surface tension or viscosity is lower than that of thefunctional material in a predetermined area on a substrate prior todischarging the functional material. In contrast, it is also possible tocarry out the method for manufacturing a color filter according to thepresent invention by discharging a liquid with a lower surface tensionand viscosity than those of the functional material to a predeterminedarea on the substrate after the functional material has been discharged.

As used herein, the following directional terms “forward, rearward,above, downward, vertical, horizontal, below and transverse” as well asany other similar directional terms refer to those directions of adevice equipped with the present invention. Accordingly, these terms, asutilized to describe the present invention should be interpretedrelative to a device equipped with the present invention.

The terms of degree such as “substantially”, “about” and “approximately”as used herein mean a reasonable amount of deviation of the modifiedterm such that the end result is not significantly changed. For example,these terms can be construed as including a deviation of at least ±5% ofthe modified term if this deviation would not negate the meaning of theword it modifies.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. Furthermore, the foregoing descriptions of theembodiments according to the present invention are provided forillustration only, and not for the purpose of limiting the invention asdefined by the appended claims and their equivalents. Thus, the scope ofthe invention is not limited to the disclosed embodiments.

1. An apparatus for manufacturing a color filter comprising: a stage onwhich a base having a target discharge area is adapted to be placed; aplurality of discharge heads having a first discharge head filled with afunctional material, and a second discharge head filled with a liquidwhose surface tension or viscosity is lower than that of the functionalmaterial; and a control unit operatively coupled to the stage and thedischarge heads, the control unit being configured to control the stageand the discharge heads such that the stage and the discharge heads moverelative to each other and a droplet of the functional material from thefirst discharge head and a droplet of the liquid from the seconddischarge head are discharged in the same target discharge area.
 2. Theapparatus for manufacturing a color filter according to claim 1, whereinthe control unit is configured to control the stage and the dischargeheads such that the liquid is discharged from the second discharged headbefore the droplet of the functional material is discharged from thefirst discharge head.
 3. The apparatus for manufacturing a color filteraccording to claim 1, wherein the control unit is configured to controlthe stage and the discharge heads such that the liquid is dischargedfrom the second discharge head toward an edge portion of the targetdischarge area on the base.
 4. The apparatus for manufacturing a colorfilter according to claim 1, wherein the liquid is a solvent for thefunctional material.
 5. The apparatus for manufacturing a color filteraccording to claim 4, wherein the liquid includes a high boiling pointsolvent for the functional material, the high boiling point solventhaving a boiling point of 250° C. or higher at one atmospheric pressure,and the functional material includes coloring ink.
 6. The apparatus formanufacturing a color filter according to claim 3, wherein the controlunit is configured to control the stage and the discharge heads suchthat the liquid is discharged from the second discharge head only towardthe edge portion of the target discharge area on the base.
 7. Theapparatus for manufacturing a color filter according to claim 1, whereinthe surface tension of the liquid is lower than that of the functionalmaterial.